Not banned, placed on the Index until corrected.

The Times Higher Education has an article entitled Drugs ban is ‘scientific censorship’, says paper, which is concerned with the fact that the political ban on various recreational drugs hinders scientific research on those substances. The article and the paper it is reviewing make, what I think is, an important point and one that should be addressed but it also contains the following, in my opinion, unfortunate historical statement:

“The outlawing of psychoactive drugs amounts to the worst case of scientific censorship since the Catholic Church banned the works of Copernicus and Galileo,” said Professor Nutt.

Why unfortunate? Well you see the Catholic Church never actually banned the works of Copernicus. First off there were no works, plural, but just one, his De revolutionibus. Secondly contrary to the widely held belief it was never banned by the Catholic Church or anybody else for that matter. Following the challenge to their authority by Galileo Galilei and Paolo Antonio Foscarini in interpreting holy scripture in 1615 and the Commission of Qualifiers judgment in 1616 that the proposition that ‘the sun is the centre of the world and completely devoid of local motion is foolish and absurd in philosophy, and formally heretical since it explicitly contradicts many places the sense of Holy Scripture’ De revolutionibus was not banned but placed on the Index until corrected.

Now this might seem like a case of splitting hairs, De revolutionibus was placed on the Index of forbidden books, total censorship end of the story. However this is far from being the case. The clue is in the addition ‘until corrected’. This meant that if those passages that stated that the heliocentric hypothesis was a fact were suitably modified back to being a hypothesis then the book would be removed from the Index.

What most people don’t realise is that this is exactly what happened. De revolutionibus was with surprisingly few minor alterations already removed from the Index in 1621 and any Catholic was free to study it in this modified form. In fact Galileo’s own personal copy with the modifications glued into place still exists.

Interesting in this context is that even this very mild censorship seems only to have been effective in Italy. The only surviving copies, which have been modified, are almost all in Italy. Outside of Italy nobody seems to have taken the Vatican’s censorship seriously not even in other Catholic countries.

Why history?

Recently there has been much criticism of the utility, or rather lack of it, of the humanities in general and of history in particular. Reduced to its simplest clichéd form, history doesn’t have any practical application why should it be supported or financed? As today is the fourth birthday of this blog I have decided to wax a little philosophical about my own personal justification for doing history in general and the history of science in particular. This is neither intended to be an academic thesis answering all possible criticisms of the utility of history nor is it intended to be a universal solution justifying the pursuit of history for everyman. It is a loose collection of personal thoughts about why I do what I do, nothing more and nothing less.

I was born loving history I can’t remember a time in my life when I wasn’t captivated and enthralled by one or other aspect of humanities past. Now I’m quite happy to admit that as a little boy growing up in post war Britain my initial enthusiasm was for tales of daring do of warriors and heroes. I loved the Wild West, the Vikings, the Roman legions as well as the recent World War and its not so distant predecessor. However it was not all too long before I began to read historical accounts of the Earp Brothers and what really happened at the OK Corral, to learn about the constitution and structure of those Roman Legions and to trace the routes of those Viking voyages. I yearned to learn the historical facts behind the stories. Whilst still at primary school my deepest historical studies concerned the tanks and planes of the two World Wars spurred on by the construction of those plastic Airfix kits. I didn’t just build tanks I researched them. I knew all about Little Willie and Big Willie the first British tanks developed in WWI and even de Mole’s tank, the vastly superior model suggested by an Australian engineer in 1911, but never built. I took my war history very seriously, supported I have to say by a father who was a professional historian.

The next sentence should be approached with caution by any mathophobics who might have wandered on to the page. I was also born loving mathematics. I had a passion for numbers and all that you can do with them from the very first time I encountered them. I love all things mathematical and always have and always will. As I’ve mentioned more than once when I was about sixteen my historian father gave me a copy of Eric Temple Bell’s Men of Mathematics, a terrible book as I now recognise, but one that opened up the world of the history of mathematics to me. My two great loves had got married. Now possibly the greatest failing in my life was that nobody suggested to me that I could become a historian of mathematics something that never occurred to me as a teenager searching for a direction in life; what happened instead needs a little explain.

First off there was a minor disaster as I took my O-levels at my very elite grammar school. In that year about 80% or more of the pupils who took history O-level on that particular examination board failed the exam dismally. I was one of the few that actually passed although with an abysmal grade. There was of course the expected groaning and gnashing of teeth with headmasters and concerned parents petitioning, cajoling and threatening the examination board who remained impervious to their pleas refusing to even consider changing their grading. Having achieved excellent grades, as expected, in maths, physics and chemistry I now went on to study them at A-level. Now in my first year sixth and my second as a boarder at said elite grammar school I was not a happy bunny. In fact I was deeply unhappy for various reasons and heading straight on into disaster. It came as no surprise when I was summoned to the headmaster’s study. Now being an incredibly ancient and extremely elite grammar school being summoned to the head’s study was the mental equivalent of being forced to walk the plank but in my then mental state I didn’t really care a damn. During the ensuing interview between headmaster and bloody-minded schoolboy the headmaster asked, not unreasonably, “what do you want to study when you leave school?” This was a school that assumed automatically, if you were doing A-levels you would go to university. My spontaneous answer, and it came without any thought whatsoever, was “history”. The, again not unreasonable, response, “so why are you doing science A-levels?” “Because that’s what I’m good at!” Now said headmaster could have told me to stop being silly and thrown me out on my ear but he didn’t. Instead he suggested I could become an archaeologist, as this could be studied with science A-levels leading to a BSc instead of a BA and so it came about that I spent the Easter school holidays on my first excavation in Chelmsford.

This proved to be rather enjoyable and was followed by more digging in the evenings and at weekends on the bank and ditch of Colchester Castle. In the summer I packed my things and went off to dig on the Roman fort at Usk in Monmouthshire, a Cardiff University dig and at that time the second largest excavation in Great Britain. The following summer having finished my A-levels I returned to Usk now an experienced and seasoned digger at the tender age of eighteen. That summer I got to know many of the first year Cardiff archaeology students who were serving part of their compulsory twelve weeks of digging, then part of the Cardiff degree course. One of these was a brash, exuberant, loud mouthed young man by the name of Peter Hill who would go on to become a good friend over many years. One day Pete was pontificating, as was his want, on the subject of archaeology when he pointed out that our principle function as archaeologists was to entertain the public/tax payers who paid the money that made our existence possible. In those days excavations were still financed by the government. Now I have never forgotten Pete’s words and I still consider them to be one of the justifications for doing history, one that some of my fellow historians might reject, we are entertainers.

Now when I use the word entertainer I am not making the modern distinction between art and entertainment, the one highbrow the other low. Here the word entertain encompasses the arts, literature, music and also history. It’s a variation on the old Bible saying, “man shall not live on bread alone”. Just as art or music fulfils some inner, dare I say spiritual, desire in many people so too history. The truth of this can be found all over our society and I think needs no further justification. However I think it is a truth often forgotten, or even suppressed, by academic historians, we are entertainers.

Of course history functions as more than entertainment and I would now like to turn my attention to another aspect based on a play on words. History is his story or her story or our story or their story or maybe just my story. In German the relationship between history and story telling is even more direct as the German word for history is Geschichte and the German word for story is also Geschichte. If I were just to remain by history as story telling I would be repeating my previous point of history as entertainment but I want to take this thought in a different direction provoked by the English play on words, history is his story.

Central to the mental health of all human beings is their sense of identity both as an individual and as part of a whole, a society, a people, or whatever. Implicitly and explicitly we define ourselves and in so doing we create our identity. Our history, that is the story of where we come from and how we got here is a major part of that defining process. We talk of roots and traditions and of belonging to groups that have histories. History plays a major role in identity. Now I realise that this claim comes dangerously close to sounding like the pedagogical idealism of people like Britain’s current Minister of Education Michael Gove, who wishes to impose a narrow nationalist history curriculum on English school children because they should learn what it means to be British. However what Gove is proposing is actually a perversion and a misuse of what I am trying to express. By manipulating and editing history he is trying to create a false identity. Using falsified history, even if only falsified through selective presentation, is a propaganda weapon used by many politicians over the centuries and one which historians must, if necessary, be prepared to confront and expose for what it is by presenting the real uncensored history.

Turing to my own small area of history’s vast canvas, the history of science, it was traditional to restrict history as identity to political history, often called scornfully the history of kings, in the twentieth century this was often expanded to include first social history and then cultural history but history of science is usually left out and ignored. I think that at no other time has an awareness and knowledge of the history of science been so important exactly because of the role that history plays in defining identity. We live in a society that is totally defined and dominated by science and technology in a way that has never before been the case. Above all technology has for several millennia played a significant role in defining the various and myriad human societies but a society that has been so completely dominated by its science and technology, as ours is has never before existed. I believe passionately that an understanding of the historical process that brought us to this situation is necessary if we are not to become alienated from this all-dominant aspect of our society and thereby lose an important facet of our own identity. Science and technology play an important role in defining us we need, in my opinion, to understand how this came about in order to maintain control of our own identities.

Before I close this already overlong series of meandering thoughts there is one last aspect of the history of science that I wish to briefly elucidate. As all ready stated we live in a society dominated by science and technology and as a result there exists a major desire to understand how science develops or as I prefer to say, evolves. The reasons for this are largely political, how can we control that evolution, direct it to solve the problems we need to solve? How can we invest our money in science to get the best returns for our investments? How should we best educate the next generations to obtain the scientists of the future that we will need? The answers to these and other similar questions are searched for in a discipline now called science studies the core of which is a mixture of philosophy and sociology of science. I belong to that group who believe that any such studies that ignore the history of science and the examination of how science actually evolved throughout history is doomed to fail. History is the laboratory that allows us to examine and dissect the evolution of the scientific disciplines. As Lakatos said without history of science philosophy of science is empty, a dictum that continues to inform my own endeavours.

As I stated at the beginning the thoughts expressed above are my personal answer to the question, “why history”. Anybody who has a different answer or wishes to criticise, refute or ridicule my answer is, as always, welcome to do so in the comments. That’s what they’re there for.

A mind bogglingly stupid statement!

In an interview with the Sydney Morning Herald the British “poster boy of pop science”^TM made the following series of statements:

“When you’ve got difficult economic times, you see governments saying, ‘Well, maybe we should cut back on this kind of blue-sky stuff.’ It’s just drivel. Imagine if that had happened in 1799 when the Royal Institute [sic] was being set up. Then, in the worst-case scenario, you don’t get electricity.” [my emphasis]

Let us take a brief look at a list of some of the prominent names associated with the evolution of the science of electricity between 1600 and 1900. This list is of course by no means exhaustive:

William Gilbert, Otto von Guericke, Robert Boyle, Stephen Gray, Francis Hauksbee, John Desaguliers, C. F. du Fay, Abbé Nollet, Pieter van Musschenbroek, Benjamin Franklin, Charles-Augustin de Coulomb, Luigi Galvani, Alessandro Volta, Hans Christian Ørsted, André-Marie Ampère, Michael Faraday, Georg Simon Ohm, James Clerk Maxwell, Galileo Ferraris, Oliver Heaviside, Charles Parsons, Joseph Swan, Thomas Edison, Nikola Tesla, Ernst Werner von Siemens and William Thomson.

Your quiz question for today, which of the men in this list were not involved with the Royal Institution?

Now some of you might accuse me of just being nasty to the “poster boy of pop science”^TM, as he was obviously referring to Michael Faraday who did work for the Royal Institution from 1813 (unlike any of the others) and who is normally credited with having invented the electric generator or more accurately discovered the principle of electromagnetic induction on which the generator is based. So is the “poster boy of pop science”^TM right after all?

Well, the question is, as always, given the general developments in electrical research at the beginning of the 1830s, might it not be possible that someone else would have discovered this principle and thus we would have had electricity with or without Faraday? Are we going to replace one dubious hypothetical with another one? Well, actually no! We just have to take a somewhat closer look at the history of electricity to discover that is exactly what happened.

Both the Italian Francesco Zantedeschi and the American Joseph Henry discovered the principle of electromagnetic induction before Faraday. Zantedeschi published his discovery, which however went unnoticed, while Henry first published when he realised that he had been beaten to the punch by Faraday. If this wasn’t enough to show that we would have had electricity if Faraday and the Royal Institution had never existed the Hungarian inventor Ányos István Jedlik actually invented a generator, superior to Faraday’s, several years before Faraday made his legendary discovery.

As I’ve said on several occasions in the past statements in the history of science and technology along the lines of if it hadn’t been for X we wouldn’t have Y are almost inevitably wrong and are on close inspection likely to leave their utterer looking pretty stupid.

Nicolaus was not a priest.

Erik Kwakkei (@erik_kwakkei) drew my attention to a rather nice short video from Prager University by Anthony Esolen of Providence College explaining that the Middle Ages were anything but Dark and should actually be called the bright ages. This is a very well done little piece managing to correct a whole series of myths in a very short time span. However I can’t resist taking a pot shot at his completely inaccurate description of Nicolaus Copernicus.

Esolen says:

Nicolaus Copernicus was, “a priest astronomer at a Polish university”.

The only part of this brief statement that is correct is that Copernicus was an astronomer.  However, it is important to point out that he was only ever an amateur astronomer; astronomy was his hobby so to speak. He never taught it at a university.

Copernicus started his undergraduate studies at the University of Kraków in Poland but left without taking a degree. He continued his studies a various universities in Northern Italy, where he studied law and medicine, not astronomy, completing his studies in 1503 with a doctorate in canon law from the University of Ferrara.

Already as a teenager Copernicus had been appointed a cannon canon of the Chapter of Frauenburg Cathedral in Warmia, where his Uncle Lucas Watzenrode was Prince Bishop. The cannons canons of the cathedral were the administration or government of Warmia.

After graduation Copernicus became private physician and secretary to his Uncle. Later he served the chapter in numerous administrative positions until his death in 1543, this being his profession and not astronomy.

Although attached to the cathedral all of his life Copernicus never took holy orders and was thus never a priest. The false claim that he was appears to have been put into the world by Galileo.

As always I find it disappointing that in an otherwise good video disposing of myths about the Middle Ages the one sentence about Copernicus should consist of false facts. A little bit of research, about five minute, could have avoided this piece of stupidity.

5 Brilliant Mathematicians – 4 Crappy Commentaries

I still tend to call myself a historian of mathematics although my historical interests have long since expanded to include a much wider field of science and technology, in fact I have recently been considering just calling myself a historian to avoid being pushed into a ghetto by those who don’t take the history of science seriously. Whatever, I have never lost my initial love for the history of mathematics and will automatically follow any link offering some of the same. So it was that I arrived on the Mother Nature Network and a blog post titled 5 brilliant mathematicians and their impact on the modern world. The author, Shea Gunther, had actually chosen 5 brilliant mathematicians with Isaac Newton, Carl Gauss, John von Neumann, Alan Turing and Benoit Mandelbrot and had even managed to avoid the temptation of calling them ‘the greatest’ or something similar. However a closer examination of his commentaries on his chosen subjects reveals some pretty dodgy not to say down right crappy claims, which I shall now correct in my usual restrained style.

He starts of fairly well on Newton with the following:

There aren’t many subjects that Newton didn’t have a huge impact in — he was one of the inventors of calculus, built the first reflecting telescope and helped establish the field of classical mechanics with his seminal work, “Philosophiæ Naturalis Principia Mathematica.” He was the first to decompose white light into its constituent colors and gave us, the three laws of motion, now known as Newton’s laws.

But then blows it completely with his closing paragraph:

We would live in a very different world had Sir Isaac Newton not been born. Other scientists would probably have worked out most of his ideas eventually, but there is no telling how long it would have taken and how far behind we might have fallen from our current technological trajectory.

This is the type of hagiographical claim that fans of great scientists tend to make who have no real idea of the context in which their hero worked. Let’s examine step by step each of the achievements of Newton listed here and see if the claim made in this final paragraph actually holds up.

Ignoring the problems inherent in the claim that Newton invented calculus, which I’ve discussed here, the author acknowledges that Newton was only co-inventor together with Leibniz and although Newton almost certainly developed his system first it was Leibniz who published first and it was his system that spread throughout Europe and eventually the world so no changes here if Isaac had not been born.

Newton did indeed construct the first functioning reflecting telescope but as I explained here it was by no means the first. It would also be fifty years before John Hadley succeeded in repeating Newton’s feat and finally making the commercial production of reflecting telescopes viable. However Hadley also succeeded in making working models of James Gregory’s reflecting telescope, which actually predated Newton’s and it was the Gregorian that, principally in the hands of James Short, became the dominant model in the eighteenth century. Although to be fair one should mention that William Herschel made his discoveries with Newtonians. Once again our author’s claim fails to hold water.

Sticking with optics for the moment it is a little know and even less acknowledge fact that the Bohemian physicus and mathematician Jan Marek Marci (1595 – 1667) actually decomposed white light into its constituent colours before Newton. Remaining for a time with optics, James Gregory, Francesco Maria Grimaldi, Christian Huygens and Robert Hooke were all on a level with Newton although none of them wrote such an influential book as Newton’s Optics on the subject. Now this was not all positive. Due to the influence won through the Principia, The Optics became all dominant preventing the introduction of the wave theory of light developed by Huygens and Hooke and even slowing down its acceptance in the nineteenth century when proposed by Fresnel and Young. If Newton hadn’t been born optics might even have developed and advance more quickly than it did.

This just leaves the field of classical mechanics Newton real scientific monument. Now, as I’ve pointed out several times before the three laws of motion were all borrowed by Newton from others and the inverse square law of gravity was general public property in the second half of the seventeenth century. Newton’s true genius lay in his mathematical combination of the various elements to create a whole. Now the question is how quickly might this synthesis come about had Newton never lived. Both Huygens and Leibniz had made substantial contribution to mechanics contemporaneously with Newton and the succeeding generation of French and Swiss-German mathematicians created a synthesis of Newton’s, Leibniz’s and Huygens’ work and it is this that is what we know as the field of classical mechanics. Without Newton’s undoubtedly massive contribution this synthesis might have taken a little longer to come into being but I don’t think the delay would have radically changed the world in which we live.

Like almost all great scientists Newton’s discoveries were of their time and he was only a fraction ahead of and sometimes even behind his rivals. His non-existence would probably not have had that much impact on the development of history.

Moving on to Gauss we will have other problems. Our author again makes a good start:

Isaac Newton is a hard act to follow, but if anyone can pull it off, it’s Carl Gauss. If Newton is considered the greatest scientist of all time, Gauss could easily be called the greatest mathematician ever.

Very hyperbolic and hagiographic but if anybody could be called the greatest mathematician ever then Gauss would be a serious candidate. However in the next paragraph we go off the rails. The paragraph starts OK:

Carl Friedrich Gauss was born to a poor family in Germany in 1777 and quickly showed himself to be a brilliant mathematician. He published “Arithmetical Investigations,” a foundational textbook that laid out the tenets of number theory (the study of whole numbers).

So far so good but then our author demonstrates his lack of knowledge of the subject on a grand scale:

Without number theory, you could kiss computers goodbye. Computers operate, on a the most basic level, using just two digits — 1 and 0…

Here we have gone over to the binary number system, with which Gauss book on number theory has nothing to do, what so ever. In modern European mathematics the binary number system was first investigated in depth by Gottfried Leibniz in 1679 more than one hundred years before Gauss wrote his Disquisitiones Arithmeticae, which as already stated has nothing on the subject. The use of the binary number system in computing is an application of the two valued symbolic logic of George Boole the 1 and 0 standing for true and false in programing and on and off in circuit design. All of which has nothing to do with Gauss. Gauss made so many epochal contributions to mathematics, physics, cartography, surveying and god knows what else so why credit him with something he didn’t do?

Moving on to John von Neumann we again have a case of credit being given where credit is not due but to be fair to our author, this time he is probably not to blame for this misattribution.  Our author ends his von Neumann description as follows:

Before his death in 1957, von Neumann made important discoveries in set theory, geometry, quantum mechanics, game theory, statistics, computer science and was a vital member of the Manhattan Project.

This paragraph is fine and if Shea Gunther had chosen to feature von Neumann’s invention of game theory or three valued quantum logic I would have said fine, praised the writer for his knowledge and moved on without comment. However instead our author dishes up one of the biggest myths in the history of the computer.

…he went on to design the architecture underlying nearly every single computer built on the planet today. Right now, whatever device or computer that you are reading this on, be it phone or computer, is cycling through a series of basic steps billions of times over each second; steps that allow it to do things like render Internet articles and play videos and music, steps that were first thought up by John von Neumann.

Now any standard computer is called a von Neumann machine in terms of its architecture because of a paper that von Neumann published in 1945, First Draft of a Report on the EDVAC. This paper described the architecture of the EDVAC one of the earliest stored memory computers but von Neumann was not responsible for the design, the team led by Eckert and Mauchly were. Von Neumann had merely described and analysed the architecture. His publication caused massive problems for the design team because the information now being in the public realm it meant that they were no longer able to patent their innovations. Also von Neumann’s name as author on the report meant that people, including our author, falsely believed that he had designed the EDVAC. Of historical interest is the fact that Charles Babbage’s Analytical Engine in the nineteenth century already possessed von Neumann architecture!

Unsurprisingly we walk straight into another couple of history of the computer myths when we turn to Alan Turing.  We start with the Enigma story:

During World War II, Turing bent his brain to the problem of breaking Nazi crypto-code and was the one to finally unravel messages protected by the infamous Enigma machine.

There were various versions of the Enigma machine and various codes used by different branches of the German armed forces. The Polish Cipher Bureau were the first to break an Enigma code in 1932. Various other forms of the Enigma codes were broken by various teams at Bletchley Park without Turing. Turing was responsible for cracking the German Naval Enigma. The statement above denies credit to the Polish Cipher Bureau and the other 9000 workers in Bletchley Park for their contributions to encoding Enigma.

Besides helping to stop Nazi Germany from achieving world domination, Alan Turing was instrumental in the development of the modern day computer. His design for a so-called “Turing machine” remains central to how computers operate today.

I’ve lost count of how many times that I’ve seen variations on the claim in the above paragraph in the last eighteen months or so, all equally incorrect. What such comments demonstrate is that their authors actually have no idea what a Turing machine is or how it relates to computer design.

In 1936 Alan Turing, a mathematician, published a paper entitled On Computable Numbers, with an Application to the Entscheidungsproblem. This was in fact one of four contemporaneous solutions offered to a problem in meta-mathematics first broached by David Hilbert, the Entscheidungsproblem. The other solutions, which needn’t concern us here, apart from the fact that Post’s solution is strongly similar to Turing’s, were from Kurt Gödel, Alonso Church and Emil Post. Entscheidung is the German for decision and the Entscheidungsproblem asks if for a given axiomatic system whether it is also possible with the help of an algorithm to decide if a given statement in that axiom system is true or false. The straightforward answer that all four men arrived at by different strategies is that it isn’t. There will always be undecidable statements within any sufficiently complex axiomatic system.

Turing’s solution to the Entscheidungsproblem is simple, elegant and ingenious. He hypothesised a very simple machine that was capable of reading a potentially infinite tape and following instruction encoded on that tape. Instruction that moved the tape either right or left or simply stopped the whole process. Through this analogy Turing was able to show that within an axiomatic system some problems would never be Entscheidbar or in English decidable. What Turing’s work does is, on a very abstract level, to delineate the maximum computability of any automated calculating system. Only much later, in the 1950s, after the invention of electronic computers a process in which Turing also played a role did it occur to people to describe the computational abilities of real computers with the expression ‘Turing machine’.  A Turing machine is not a design for a computer it is term used to described the capabilities of a computer.

To be quite open and honest I don’t know enough about Benoit Mandelbrot and fractals to be able to say whether our author at least got that one right, so I’m going to cut him some slack and assume that he did. If he didn’t I hope somebody who knows more about the subject that I will provide the necessary corrections in the comments.

All of the errors listed above are errors that could have been easily avoided if the author of the article had cared in anyway about historical accuracy and truth. However as is all to often the case in the history of science or in this case mathematics people are prepared to dish up a collection of half baked myths, misconceptions and not to put too fine a point on it crap and think they are performing some sort of public service in doing so. Sometimes I despair.

 

Cartographical Claptrap!

The AEON magazine website has a long essay[1] by Kurt Hollander simply titled Middle Earth that takes as its subject not the fantasy realm of J. R. R. Tolkien but the equator, the imaginary line marking the middle of the Earth’s sphere. Unfortunately this essay is severely marred by a series of errors, myths and falsities about the history of cartography and geodesy. I have selected some of the worst here for critical analysis and correction.

Our author gets off to a flying start with the biggest geodesic myth of them all:

Medieval Christian mapmakers, familiar only with a small corner of the planet, worked within strict horizons that were fixed by the Church’s interpretation of the Bible. Their Earth was flat.

My friend Darrin Hayton (@dhayton) has written several posts on the excellent PACHS blog over the years criticising the people who still insists on propagating the myth that the Europeans in the Middle Ages believed that the world was flat. Just once more for those that haven’t been listening, they didn’t. That the world was a sphere was probably first recognised by the Pythagoreans in the sixth century BCE and almost all educated people accepted this fact from at the latest the fourth century BCE up to the present.

First created in the 7th century, the Christian orbis terrarum (circle of the Earth) maps, known for visual reasons as ‘T-and-O’ maps, included only the northern hemisphere.

T and O maps actually have their roots in Greek geography and cartography and only display part of the northern hemisphere because that was all that their creators knew about.

The T represented the Mediterranean ocean, which divided the Earth’s three continents — Asia, Africa, and Europe — each of which was populated by the descendants of one of Noah’s three sons. Jerusalem usually appeared at the centre, on the Earth’s navel (ombilicum mundi), while Paradise (the Garden of Eden) was drawn to the east in Asia and situated at the top portion of the map. The O was the Ocean surrounding the three continents; beyond that was another ring of fire.

Given that the Greeks, the originators of the geography on which the T and O maps are based, lived in the Mediterranean Sea (not ocean!) they were of course well aware of the fact that it is not T shaped. The T on T and O maps actually represents in schematic form the Mediterranean and the Don and Nile rivers, as the dividing lines between the three known continents.

For the Catholic Church, the Equator marked the border of civilisation, beyond which no humans (at least, no followers of Christ) could exist. In The Divine Institutes (written between 303 and 311CE), the theologian Lactantius ridiculed the notion that there could be inhabitants in the antipodes ‘whose footsteps are higher than their heads’. Other authors scoffed at the idea of a place where the rain must fall up. In 748, Pope Zachary declared the idea that people could exist in the antipodes, on the ‘other side’ of the Christian world, heretical..

As has been pointed out by numerous people writing about the flat earth myth, Lactantius had almost no supporters of his theories.

This medieval argument was still rumbling on when Columbus first sailed southwest from Spain to the ‘Indies’ in 1492. Columbus, who had seen sub-Saharans in Portuguese ports in west Africa, disagreed with the Church: he claimed that the Torrid Zone was ‘not uninhabitable’.

Our author appears to be prejudiced against the Portuguese. Throughout the fifteenth century in a series of expeditions, started by Henry the Navigator (1394 – 1460), a succession of Portuguese explorers had been venturing further and further down the West African coast reaching the Gulf of Guinea, which lies on the equator, in 1460. These expeditions reached a climax in 1488, four years before Columbus set sail to the Indies, when Bartolomeu Dias rounded the tip of South Africa proving that one could reach the Indian Ocean by sea and pathing the way for Vasco de Gama’s 1497 voyage to India.

Although he never actually crossed the Equator, he did go beyond the borders of European maps when he inadvertently sailed to the Americas. To navigate, Columbus used, among others, the Imago Mundi (1410), a work of cosmography written by the 15th-century French theologian Pierre d’Ailly, which included one of the few T-and-O maps with north situated at the top.

The importance of Pierre d’Ailley’s Imago Mundi for Columbus lay not in the orientation of its T and O map but in the fact that d’Ailley severely underestimated the circumference of the globe thus making Columbus’ attempt to sail westward to the Indies seem more plausible than it in reality was.

Columbus’s eventual ‘discovery’ of America stretched the horizons of the European mind. The Equator was gradually reimagined: no longer the extreme limit of humanity, a geographical hell on Earth, it became simply the middle of the Earth.

In particular, Cobo has problems with the direction that mapmaking has taken. In 150AD, Ptolemy drew the first world map with north placed firmly at the top.

Earlier Greek geographers such as Eratosthenes, who also drew world maps, almost certainly also drew their maps with north at the top. Ptolemaeus is not the beginning but the culmination of Greek cartography.

This orientation has become the standard one for maps everywhere. The preeminence of north derives from the use of Polaris, also known as the North Star, as the guiding light for sailors.

This is a piece of pure fantasy on the part of out author. To quote Jerry Brotton from his excellent A History of the World in Twelve Maps, “Why north ultimately triumphed as the prime direction in the Western geographical tradition, especially considering its initial negative connotations for Christianity […], has never been fully explained. Later Greek maps and early medieval sailing charts, or portolans, were drawn using magnetic compasses, which probably established the navigational superiority of the north-south axis over an east-west one; but even so there is little reason why south could not have been adopted as the simplest point of cardinal orientation instead, and indeed Muslim mapmakers continued to draw maps with south at the top long after the adoption of the compass.”[2] I would add to this the fact that many European Renaissance maps also had south at the top.

Yet Polaris, or any other star for that matter, is not a fixed point. Because of the Sun and Moon’s gravitational attraction, the Earth actually moves like a wobbling top. This wobble, known to astronomers as the precession of the Equator, represents a cyclical shift in the Earth’s axis of rotation. It makes the stars seem to migrate across the sky at the rate of about one degree every 72 years. This gradual shift means that Polaris will eventually cease to be viewed as the North Star, and sailors will have to orient themselves by other means.

In 1569, the Flemish cartographer Gerardus Mercator, the first to mass-produce Earth and star globes,

Geradus Mercator (1512 – 1594) was not the first to mass-produce Earth and star globes Johannes Schöner  (1477 – 1547) was.

devised a system for projecting the round Earth onto a flat sheet of paper.

Our author, probably unintentionally or at least I hope so, creates the impression that Mercator was the first to devise a map projection from the sphere onto a flat sheet of paper; he, of course, wasn’t. This achievement is usually credited to Eratosthenes in the third century BCE. Ptolemaeus’ Geographia (about 150 CE) outlines three different map projections.

His ‘new and augmented description of Earth corrected for the use of sailors’ made the Earth the same width at the Equator and the poles, thus distorting the size of the continents. Although Mercator created his projection (still used today in almost all world maps) for navigation purposes, his scheme led to a bloated sense of self for the northern countries, located at the top of the map, while diminishing the southern hemisphere’s sense of size and importance.

Our author is rather vague about how or why this distortion occurs. Because the distance between the parallels of longitude in the Mercator projection increases the further one moves from the equator, landmasses become distorted in area (larger than they are in reality) the further they are away from the equator. Because the major landmasses in the northern hemisphere are further removed from the equator than those in the southern hemisphere they take on an illusionary physical dominance.

Might I, not so politely, suggest to Mr Hollander that if he wishes to write about the history of cartography in the future that he indulges in some proper research of the subject before he puts finger to keyboard.

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[1] I’m not sure whether I should thank or curse Richard Carter FCD (@friendsofdarwin) for drawing my attention to this essay. Whichever, he is to blame for the existence of this post.

[2] Jerry Brotton, A History of the World in Twelve Maps, Allen Lane, London, 2012, p. 11

Celebrating Denis Papin

The commune of Chitenay and the city of Blois in France are celebrating the three hundredth anniversary of the death of one of their sons, Denis Papin (22 August 1722 – exact date of death unknown) the inventor of the atmospheric steam engine, about whom I have blogged in the past.

You can read about the planned celebrations from 19^th to 21^rd July here in French. The Trevithick Society, who honour the memory of Richard Trevithick realiser of the high pressure steam engine and railway pioneer, have been invited to take part in the celebrations and you can read their account of the celebrations here in English.

My ICHS nightmare.

If you are attending this year’s history of science and all the rest monster bean feast in Manchester in July and are holding a lecture there for the first time in your life at a major conference then I recommend that you stop reading this post.

In 1980 I moved from Britain to German and made my home there. It was a move that was determined by a random chain of events rather than any sort of positive decision. Once settled in Germany I needed to do a series of things such as, for example, find work or learn the language. After some time I found out that the best German as a foreign language course available locally was at the University in Erlangen not far from where I was living at the time. Upon investigation I discovered that to enrol in the course I first had to enrol in the university in a regular course of study. Now I was a classic nineteen seventies drop out who had originally studied archaeology in Cardiff but who had always intended to return to university when I had discovered what I really wanted to study. Now the time seemed to have come for me to resume my academic career and I enrolled in the university to study mathematics with philosophy as my subsidiary subject and after a year of learning German I became a mature maths student studying for the equivalent of a master’s degree, in those days the first degree in Germany.

Now my principle interest in mathematics was in its history for which the Erlangen maths institute had little interest but by a strange twist of fate my philosophy professor was a practicing historian of mathematics. After three years, at about bachelor’s level, I dropped mathematics and took up philosophy, concentrating on history and philosophy of science, as my major with English philology and history as my subsidiaries. By now my philosophy professor had asked me if I wished to work in a research project into the external history of mathematical logic, a chance I jumped at and which became my apprenticeship as a historian of science. I worked in this project in total for around ten years.

In 1989 the International Congress for the History of Science XVIII (ICHS), as it was then, came to Germany and because they couldn’t decide which city should have the privilege of putting it on, the first half took place in Hamburg and the second in Munich, the two of them a mere 790 kilometres apart. Not only did we attend but our research project was a section in its own right with legendary Dutch-American Marxist historian of mathematics Dirk Struik, then 95 years old, as our keynote speaker.

I was due to hold a talk on nineteenth century Scottish logician Hugh MacColl, the intended subject of my master’s thesis. Although I was already approaching forty and had quite a lot of experience lecturing at my home university this was to be my first lecture at a big conference and this with around twelve hundred delegates, if my memory serves me correctly, was the biggest conference that the history of science had to offer. I was to say the least somewhat nervous.

Finally the big day dawned and taking my place at the lectern I was introduced by my professor, who was chairing the session, to the seventy or eighty assembled listeners waiting to hear my talk.

 The author apprehensively preparing to present his lecture Munich 7.8.1989

(Photo: Volker Peckhaus)

Suffering from a good portion of stage fright I stumbled out the first sentences of my talk and I was just beginning to come into swing when the door crashed open stopping me in mid sentence and riveting the attention of everybody in the room. One of the organisers stomped through the doorway and marched with determined strides across the room to the desk on the podium where my professor was sitting, his footfalls booming out into the stunned silence like the steps of a jackbooted military officer on his way to an execution in a Hollywood B movie. Reaching the desk he ripped off the conference timetable that was taped to its surface replacing it with a new one, which he taped into place, tearing long strips of adhesive tape from a roll with a noise that seemed to rent the very air in the room. He then turned and with the same purposeful stride marched out of the room banging the door shut with a final clap of doom as he exited. During the whole process he uttered not a word.

I was sunk. Whatever faint shreds of confidence I might have had before his appearance were blown away leaving me a gibbering wreck staring at the listeners who of course were no longer paying any attention to me. Somehow I managed to stumbled through my presentation feeling like I was battling through a thick mental fog and mumble some sort of answers to the few polite questions proffered at the end but what should have been the glorious highpoint to my career as a historian of logic at that point of my life had turned into a nightmare.

The Phlogiston Theory is not equivalent to the Aquatic Ape Hypothesis.

In recent days the Internet science community has got its collective nickers in a mighty twist. The disciples of the Aquatic Ape Hypothesis (AAH) have dared to hold an international congress in London and the, oh so irresponsible, press has wasted precious print and cyber space reporting on this frivolity. For those not in the know the Aquatic Ape Hypothesis claims that certain aspects of human evolution can only be explained by assuming that a group of anthropoids, the future humans, lived for a substantial period in water. My evolutionary theory expert friends assure me that this hypothesis is a festering heap of non-scientific nonsense, as was forcibly expressed by Henry Gee in this Guardian blog post. So far so good but a couple of science writers thought it would be a good idea to draw parallels between the AAH and one or other historical scientific theory with disastrous results.

The first of these was Ben Richmond writing on The Mother Board in his post How the Aquatic Ape Theory Keeps Floating On. Mr Richmond chose to equate the AAH with the Ptolemaic geocentric theory. He wrote:

But the aquatic apes theory is more like Ptolemaic models of the cosmos that Copernicus overthrew. These models of the solar system had to be ever more complex to keep the Earth in the middle and also account for the incongruous movement of the planets. In the end Copernicus’s moving the Sun to the center of the solar system simplified the model…

This paragraph is of course a complete myth that has absolutely nothing to do with what really happened in the sixteenth century. As this is a standard myth that gets repeated time and time again I shall briefly sketch, not for the first time, the true facts of the story.

The Ptolemaic models developed in the Middle Ages, first by Islamic astronomers and then, most recently before Copernicus, by Peuerbach actually became simpler not more complex. The Peuerbachian geocentric model in use as Copernicus published his De revolutionibus was actually simpler than Copernicus’ heliocentric model. The contemporary astronomers hoped that Copernicus’ model would at least deliver more accurate data on the positions of the heavenly bodies, the, at the time, principle function of mathematical astronomy but the Copernican system based on the same data as the Ptolemaic systems was just as inaccurate as its predecessors. Heliocentricity only “overthrew” geocentricity as Kepler developed his actually simpler and much more accurate elliptical astronomy in the first quarter of the seventeenth century.

Ed Yong, notable science writer, chose a similar tactic and compared, in a tweet, the AAH not with geocentricity but with the phlogiston theory of eighteenth century chemistry.

Ed Yong tweeted:

After the recent shadow biosphere piece & this wk’s aquatic apes one, I look forward to the Obsever’s exposés on phlogiston & cold fusion

Rebecca Stewart praised his audacity in another tweet:

Phlogiston is sooo underrated!

Karen James crowned him a master tweeter for this piece of brilliance

That last tweet shows why ‪@edyong209 is considered a master tweeter. I suppose we shouldn’t be surprised; tweeting is writing, after all.

This comparison is just as wrong as Richmond’s and casts a poor light on Ed Yong for having made the comparison. Yong’s tweet and those of his supporters imply, at least unintentionally, that AAH and the phlogiston theory are equivalent in their scientific status a complete fallacy. The AAH is a highly dubious hypothesis that does not according to Henry Gee, even agree with the know facts of evolution theory whereas the phlogiston theory was an important scientific research programme, which played an important role in the evolution of chemistry in the eighteenth century.

It is very easy from our standpoint in the twenty-first century to pour scorn on the theory of phlogiston, which viewed whiggishly, that is in comparison to our current knowledge of chemistry, can in some of its aspect appear more than somewhat ridiculous. However viewed within the context of the situation in which it was born the phlogiston theory made a great deal of sense.

Phlogiston arose at the end of the seventeenth century when the dominant theory of matter was still the four-element theory of the ancient Greeks. This had been supplemented by the tria prima concept of the Paracelcians. On top of the four Greek elements of earth, water, fire and air Paracelsus had added the principles of mercury, sulphur and salt. It is important to realise that these are principles involved in the composition of substances rather than substances themselves. In an analogy based on the combustion of a piece of wood Paracelsus compared the smoke to mercury, the flame to sulphur and the ash to salt. This analogy is important, as combustion alongside distillation was one of the two principle methods of chemical investigation available to alchemists in the Early Modern Period.

Whilst rejecting Paracelcian alchemy the German physician Johann Joachim Becher (1635 – 1682) borrowed the tria prima replacing the mercury, sulphur and salt with three forms of the element earth:

terra fluida or mercurious earth, which contributed fluidity, subtility, volatility and metallicity to substances.

terra pinguis or fatty earth, which produced oily, sulphureous and combustible properties.

terra  lapidea or vitreous earth, which was the principle of fusibilty.

Becher published this theory in his Physica Subterranea in 1667. For Becher his terra pinguis played an essential role in combustion.

Another German physician Georg Ernst Stahl (1659 – 1734) took up Becher’s theory, in 1718, renaming terra pinguis, phlogiston, from the Greek meaning inflammable, using this principle to explain both combustion and corrosion (rusting). Hypothesising that all inflammable materials contain phlogiston, which is consumed or used up during combustion. The important point is that the phlogiston theory as developed by Stahl readily explained the known facts of combustion.[1]

Working within the phlogiston research programme, in particular English chemists such as Joseph Black, Daniel Rutherford, Henry Cavendish, James Watt and Joseph Priestley isolated and discovered a whole range of elemental and compound gasses and furthered the evolution of chemistry over the next sixty or seventy years. In fact it was using the discoveries of the phlogistonists that Lavoisier and others were able to produce the synthesis that became known as modern chemistry. This dependence on the phlogistonists was so great that the great German nineteenth century chemist Justus Freiherr von Liebig stated in his third Familiar Letter on Chemistry: “He discovered no new body, no new property, no natural phenomenon previously unknown; but all the facts established by him were the necessary consequences of the labours of those who preceded him.”[2]

Supplanted by the Lavoisier’s synthesis phlogiston became an obsolete theory one that viewed from the new standpoint of the facts that it had discovered was no longer able to explain the available evidence a fate it was soon to share with Lavoisier’s own contribution to the evolution of chemistry.

Above I said that viewed whiggishly, that is in comparison to our current knowledge of chemistry, can in some of its aspect appear more than somewhat ridiculous. Interestingly the, now, Cambridge historian of chemistry Hasok Chang has written a brilliant paper titled We Have Never Been Whiggish (About Phlogiston)[3], in which he takes a new whiggish look at the phlogiston theory and its successor. I recommend this paper to anybody wishing to equate the phlogiston theory to the AAH.

Unfortunately it is common practice for people largely ignorant of the history of science to equate modern pieces of idiocy with obsolete theories from the evolution of science that having served their purpose and having been superseded by other theories are then considered as suitable subjects for ridicule. This is wrong, with a probability approaching certainty all of the scientific theories that we use today will someday themselves be superseded by better or more explanatory theories and become in their turn obsolete. This will not make them ridiculous but they will become part of a long chain of theories that have facilitated the evolution of science. Theories that no matter how strange they might appear to us from our privileged position of hindsight should be treated with the respect that they deserve for their important contribution to the advancement of knowledge.

 

 

 

 

 

 

 

 

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[1] This very brief account of the origins of the phlogiston theory is largely taken from, William H. Brock, The Fontana History of Chemistry, Fontana Press, London, 1992, pp. 78-86.

[2] I owe this Liebig quote to regular Renaissance Mathematicus reader and commentator Arjen Dijksman (@materion) to whom I’m very grateful.

[3] Hasok Chang, We Have Never Been Whiggish (About Phlogiston), Centaurus, Vol. 51, 2009, pp. 239-264.

Gopnik, Galileo and Ed Yong: Galileo not admitting to being wrong.

Ed Yong (@edyong209) is a well-known and highly respected science writer. At regular intervals he posts lists of links on his website, Not Exactly Rocket Science, of science stories that he has found interesting, a sort of one-man blog carnival. On his links list for 20 April he included a link to Adam Gopnik’s BBC Point of View piece, which I recently criticised, with the following description.

Galileo was a great scientist because he wasn’t afraid to admit when he was wrong. If only more of us did the same.

Now in recent months we have had a series of talks and articles by such luminaries as Paul Nurse, President of the Royal Society, making similar claims for science and scientists in general. That is that scientists are characterised by their willingness to admit that they are wrong and to give up the theories they hold that have been proved to be defective. Such speeches have had historians of science all over the Intertubes banging their heads against the wall in collective displays of disbelief because even a cursory survey of the history of science would show that the exact opposite is true, scientists hang on to their cherished theories until the bitter end against all sorts of opposition and refuting evidence and Galileo is a prime example of such behaviour. For me this attitude, and it is not necessarily one that I condemn, was wonderfully summed up by Einstein when Eddington confirmed the General Theory of Relativity empirically. Asked by a reporter what he would have done if Eddington had refuted his theory Einstein is said to have replied then I would have said that Eddington’s measurement were wrong. A certain amount of tenacity is important in the early development of scientific theories, which are seldom born complete and perfect and are brought to their optimal condition through a process of criticism and modification to refute that criticism. Not giving up supposedly refuted theories is part and parcel of the scientific process but sometimes this tenacity can be and is misplaced and Galileo is one historical figure who delivers very good examples of a man who held onto wrong theories beyond the point of no return.

Galileo is well known as a supporter of Copernican heliocentricity and as one of the founders of the new mechanics but in both theories his adherence to an antiquated theory held him back an adherence that he maintained although he must have known that it was wrong. The antiquated theory that Galileo refused to abandon was the so-called Platonic axiom in astronomy. This metaphysical axiom says that the planets move with uniform motion in circles. Like Copernicus before him Galileo’s fidelity to this axiom meant the retention of the whole Ptolemaic apparatus of deferents and epicycles. Clinging to this axiom also meant that Galileo failed to formulate the principle of inertia properly as he believed, like a good Aristotelian, that only circular motion was natural motion. All well and good but why do I claim that he should have known better? The answer is Johannes Kepler.

Before Galileo had finished writing his Dialogo Kepler had already delivered his three laws of planetary motion thus completely refuting the Platonic axiom. Kepler’s laws were strict mathematical laws derived from Tycho Brahe’s empirical observations. Here was modern science in action if ever there was and Galileo ignored it clinging to the clearly refuted Greek orthodoxy, why? Faced with this seemingly inexplicable behaviour of their hero the Galileo fan club argue that Galileo could not accept Kepler’s bizarre Renaissance meta-physics and that is why he refused to accept Kepler’s work. This seems like a reasonable argument until one takes a closer look at the evidence. Kepler’s first two laws were delivered in his Astronomia Nova (1609) a book that contains none of his possibly off putting meta-physics. Also the clearest statement of his three laws and their application to a heliocentric system is in his Epitome astronomiae Copernicanae  (1617, 1620 & 1621) a textbook, which also is relatively free of anything that might have offended Galileo’s sensibilities.

I think that the answer is actually to be found in Galileo’s ego. Kepler’s work on the planetary orbits was a much better and more convincing argument for heliocentricity than anything Galileo had produced. In fact it was the Epitome Copernicanae combined with Kepler’s Rudolphine Tables that led to the acceptance of heliocentricity in the seventeenth century and not Galileo’s work.  If Galileo were to include Kepler’s work in his Dialogo then he would be merely the messenger and not the creator so he simply ignored it and stuck to the Platonic axiom that he knew to be wrong.

Galileo’s second case of refusing to admit that he was wrong is even more undignified. In 1618 a spectacularly bright comet was visible over Europe, which was of course carefully observed by nearly all the leading astronomers. One notable exception was Galileo who because of ill health had been unable to take part in the observations. By now Galileo was Northern Italy’s leading natural philosopher feted for his quick wit and his even quicker slicing tongue with which he took great pleasure in dicing his scientific opponents. Asked for his opinion on the nature of the new comet Galileo, who as already noted actually knew nothing about it, took the strange step of attacking the Jesuit astronomer Orazio Grassi who had carefully observed the comet and based on his observations had correctly calculated that the comet was a supra-lunar celestial body. Galileo now claimed that Grassi was wrong and presented what was in essence the out dated and discredited Aristotelian theory that comets were sub-lunar meteorological phenomena. This notorious dispute culminated in Galileo’s Il Saggiatore with its famous “the book of nature is written in the language of mathematics” quote. Here is Galileo bizarrely lecturing Grassi that investigations of nature must be empirical and mathematical in a situation where Grassi’s investigations were just that and Galileo’s own were definitely not. Of course Galileo’s brilliant polemic crushed his poor hard done by opponent without Galileo’s claque noticing that Grassi was in the right and Galileo very much in the wrong something that the maestro almost certainly knew, however his ego would not let him admit it. He had to win the argument at all costs even if he was horribly wrong.

We now turn to the most notorious case of Galileo refusing to accept that he was wrong his theory of the tides. This was the crowing glory of Galileo’s argumentation for heliocentricity his only empirical evidence. This took up the whole of the fourth day of his Dialogo delivering the climax and was the only argument that he brought forward in 1615 when he was trying to head off a condemnation of Copernicus by the Inquisition. This was Galileo’s trump. Unfortunately it suffered from one glaring defect it was wrong. It was empirically, irrefutably, undeniably, indisputably wrong.

This theory of the tides was first formulated in about 1596 by Galileo and Paolo Sarpi in one of their intellectual sparring sessions. In fact it is not clear if the theory is from Galileo or Sarpi, 1596 being the date that Sarpi first recorded it in his scientific diary. Of itself it is actually quite an ingenious idea. If the earth is actually moving as stipulated in a heliocentric hypothesis then wouldn’t the water on the earths surface slop around like water in a bowl being carried by someone and might this not be the explanation for the tides? If this were the case it would indeed be a solid empirical argument in favour of heliocentricity. In fact John Heilbronn in his Galileo biography dates Galileo’s conversion to Copernicanism to 1596 and the formulation of this theory.

As already stated above this theory has a major problem it was empirically refuted. As formulated by Galileo/Sarpi there would only be one tide a day but as every coastal inhabitant knows there are two. There is also another problem for this theory there already existed a better theory to explain the tides, a theory that we now know to be true; they are caused by the moon. The correlation between the tides and the phases of the moon had already been observed in antiquity but as every scientist knows, or should know, correlation does not equal causation and there was no known explanation as to how the moon could cause the tides. Newton was not even a blip on the horizon at this time.

Now Gopnik argued in his two essay’s that Galileo stuck to his refuted theory of the tides because the much more rational alternative smacked too much of magic for him to accept it, action at a distance would prove a difficult point even for Newton. Gopnik has solid evidence for his claim this is exactly the argument that Galileo brings for rejecting the lunar tide theory in book four of his Dialogo. So Gopnik is right? I don’t think he is. I think Galileo is being deceptive.

Galileo is convinced that his theory of the tides can deliver the empirical proof he so desperately needs for heliocentricity. If it were true then it would indeed the only such proof he has to offer. All the other arguments he marshals in his masterpiece are suggestive that heliocentricity might be a viable alternative but none of them is a proof or anything remotely like it. He needs his theory of the tides. He spent thirty years trying to cure its very obvious defect and failed but he is still not prepared to abandon it. Now as already pointed out there existed a much better empirically based explanation for the tides the lunar theory, one that for example Kepler backed. It of course lacked an explanatory mechanism but one could set up a research programme based on the concept of attractive forces, an idea that Kepler was already playing with, to find that mechanism, which is of course exactly what Newton did. If however Galileo accepted the greater plausibility of the lunar tide theory then his only “proof” of heliocentricity was down the drain so we look for a reason to reject it. In doing so he of course rejected the possibility of following Kepler down the path of considering forces controlling the solar system; a path that interestingly Galileo’s pupil Borelli took.

To summarise I don’t think that Galileo rejected the lunar tide theory because he thought it was magical. I think he rejected the lunar tide theory because it posed a serious threat to his own mechanical tide theory the only supposed proof that he had for a geocentric astronomy and having rejected it he looked around for an excuse to justify his rejection. There are lots of other examples of contemporary natural philosophers and astronomers employing the same tactic, Copernicus, Kepler, Newton and Galileo himself but to detail them here would make an already long post even longer. I shall save them for another post on another occasion.

As we have seen far from being unafraid to admit that he was wrong on three separate and highly significant occasion, significant for the evolution of science that is, not only did Galileo refuse to admit that he was wrong although he knew that he was but he actually did his best to bamboozle people into believing that he was right.